SwiftUI-沒有與鍵CodingKeys關聯的值

我目前正在嘗試Request在我的 SwiftUI 應用程式中撰寫一個與我正在構建的 API 一致的通用物件。我已經用 JSON 有效負載寫了一些簡單的東西，作為例子，我遇到了物件解碼的問題。下面是請求物件。

let json = """
{
    "object": "bottle",
    "has_more": false,
    "data": [
        {
          "id": "5ffa81e7-1d91-43b5-83cc-9ee1ab634c7b",
          "name": "14 Hands Hot to Trot White Blend",
          "price": "$8.99",
          "image": "https://cdn11.bigcommerce.com/s-7a906/images/stencil/1000x1000/products/8186/10996/14-Hands-Hot-to-Trot-White-Blend__56901.1488985626.jpg?c=2",
          "sku": "088586004490",
          "size": "750ML",
          "origination": "USA, Washington",
          "varietal": "White Wine",
          "information": "14 Hands Hot to Trot White Blend",
          "proof": 121.5,
          "brand_id": "1",
          "rating": 1,
          "review_count": 5
        }
    ]
}
"""

struct Request: Decodable {
    let object: String
    let has_more: Bool
    let data: [RequestData]
}

struct Bottle: Decodable {
    let id: String
    let name: String
    let price: String
    let image: String
    let sku: String
    let size: String
    let origination: String
    let varietal: String
    let information: String
    let proof: Float
    let brand_id: String
    let rating: Int
    let review_count: Int
}

enum ObjectType: String, Decodable {
    case bottle
}

enum BottleData: Decodable {
    case bottle(Bottle)
}

struct RequestData: Decodable {
    let hasMore: String
    let object: ObjectType
    let innerObject: BottleData

    enum CodingKeys: String, CodingKey {
        case hasMore
        case object
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        self.object = try container.decode(ObjectType.self, forKey: .object)
        self.hasMore = try container.decode(String.self, forKey: .hasMore)

        switch object {
        case .bottle:
            self.innerObject = .bottle(
                try Bottle(from: decoder)
            )
        }
    }
}

let decoder = JSONDecoder()
let requestData = try decoder.decode(Request.self, from: json.data(using: .utf8)!)

for data in requestData.data {
    switch data.innerObject {
    case .bottle(let bottle):
        print(bottle.name)
    }
}

嘗試測驗此物件時收到以下錯誤。

DecodingError
  ? keyNotFound : 2 elements
    - .0 : CodingKeys(stringValue: "object", intValue: nil)
    ? .1 : Context
      ? codingPath : 2 elements
        - 0 : CodingKeys(stringValue: "data", intValue: nil)
        ? 1 : _JSONKey(stringValue: "Index 0", intValue: 0)
          - stringValue : "Index 0"
          ? intValue : Optional<Int>
            - some : 0
      - debugDescription : "No value associated with key CodingKeys(stringValue: \"object\", intValue: nil) (\"object\")."
      - underlyingError : nil

鑒于我目前只有一個物件，我有點困惑為什么這不像我預期的那樣作業（沒有任何錯誤）。任何人都可以發現我在這里可能做錯了什么嗎？

uj5u.com熱心網友回復：

請仔細閱讀錯誤。

這些CodingPath組件指示錯誤的確切位置。它是

CodingKeys(stringValue: "object", intValue: nil)
CodingKeys(stringValue: "data", intValue: nil)
_JSONKey(stringValue: "Index 0", intValue: 0)
CodingKeys(stringValue: "object", intValue: nil).
 

其中 - 轉換為關鍵路徑 - 是

object.data[0].object

實際的錯誤資訊

“沒有與鍵 CodingKeys(stringValue: "object", intValue: nil) ("object") 關聯的值。”

說沒有鑰匙object的RequestData，它是真實的物件。

我想這只是一個錯字。代替

let data: [RequestData]

和

let data: [Bottle]

并洗掉RequestData和相關的結構。他們毫無意義。

編輯：

您可以執行類似的操作，但由于 JSON 僅包含一種型別，因此該解決方案僅解碼此特定 JSON

let json = """
{
    "object": "bottle",
    "has_more": false,
    "data": [
        {
          "id": "5ffa81e7-1d91-43b5-83cc-9ee1ab634c7b",
          "name": "14 Hands Hot to Trot White Blend",
          "price": "$8.99",
          "image": "https://cdn11.bigcommerce.com/s-7a906/images/stencil/1000x1000/products/8186/10996/14-Hands-Hot-to-Trot-White-Blend__56901.1488985626.jpg?c=2",
          "sku": "088586004490",
          "size": "750ML",
          "origination": "USA, Washington",
          "varietal": "White Wine",
          "information": "14 Hands Hot to Trot White Blend",
          "proof": 121.5,
          "brand_id": "1",
          "rating": 1,
          "review_count": 5
        }
    ]
}
"""

enum RequestData {
    case bottle([Bottle])
}

enum ObjectType: String, Decodable {
    case bottle
}

struct Request: Decodable {
    let object: ObjectType
    let hasMore: Bool
    let data: RequestData
    
    enum CodingKeys: String, CodingKey { case hasMore = "has_more", object, data}
    
    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        self.object = try container.decode(ObjectType.self, forKey: .object)
        self.hasMore = try container.decode(Bool.self, forKey: .hasMore)
        switch object {
            case .bottle:
                let bottleData = try container.decode([Bottle].self, forKey: .data)
                data = RequestData.bottle(bottleData)
        }
    }
}

struct Bottle: Decodable {
    let id: String
    let name: String
    let price: String
    let image: String
    let sku: String
    let size: String
    let origination: String
    let varietal: String
    let information: String
    let proof: Float
    let brand_id: String
    let rating: Int
    let review_count: Int
}

let decoder = JSONDecoder()
let requestData = try decoder.decode(Request.self, from: Data(json .utf8))
print(requestData)

標籤：迅速 迅捷

上一篇：通過"getById&save"進行的JPA物體更新并沒有更新它的更新時間戳列。

下一篇：我怎樣才能運行我從GitHub下載的Python腳本？